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| author | Peter Zijlstra <peterz@infradead.org> | 2022-06-14 23:15:59 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-25 11:26:44 +0200 |
| commit | 28aa3fa0b2c9d0cd7bdac42d9eb7fe3d5f6c79e8 (patch) | |
| tree | 7b1f182f4469bdafcff2565c008bef049cca6102 | |
| parent | 55bba093fd91a76971134e3a4e3576e536c08f5c (diff) | |
| download | linux-stable-28aa3fa0b2c9d0cd7bdac42d9eb7fe3d5f6c79e8.tar.gz linux-stable-28aa3fa0b2c9d0cd7bdac42d9eb7fe3d5f6c79e8.tar.bz2 linux-stable-28aa3fa0b2c9d0cd7bdac42d9eb7fe3d5f6c79e8.zip | |
objtool: Update Retpoline validation
commit 9bb2ec608a209018080ca262f771e6a9ff203b6f upstream.
Update retpoline validation with the new CONFIG_RETPOLINE requirement of
not having bare naked RET instructions.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: conflict fixup at arch/x86/xen/xen-head.S]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 6 | ||||
| -rw-r--r-- | arch/x86/mm/mem_encrypt_boot.S | 2 | ||||
| -rw-r--r-- | arch/x86/xen/xen-head.S | 1 | ||||
| -rw-r--r-- | tools/objtool/check.c | 19 |
4 files changed, 22 insertions, 6 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index dafaf73746eb..981e6147ca38 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -76,6 +76,12 @@ .endm /* + * (ab)use RETPOLINE_SAFE on RET to annotate away 'bare' RET instructions + * vs RETBleed validation. + */ +#define ANNOTATE_UNRET_SAFE ANNOTATE_RETPOLINE_SAFE + +/* * JMP_NOSPEC and CALL_NOSPEC macros can be used instead of a simple * indirect jmp/call which may be susceptible to the Spectre variant 2 * attack. diff --git a/arch/x86/mm/mem_encrypt_boot.S b/arch/x86/mm/mem_encrypt_boot.S index a186007a50d3..145b67299ab6 100644 --- a/arch/x86/mm/mem_encrypt_boot.S +++ b/arch/x86/mm/mem_encrypt_boot.S @@ -66,6 +66,7 @@ SYM_FUNC_START(sme_encrypt_execute) pop %rbp /* Offset to __x86_return_thunk would be wrong here */ + ANNOTATE_UNRET_SAFE ret int3 SYM_FUNC_END(sme_encrypt_execute) @@ -154,6 +155,7 @@ SYM_FUNC_START(__enc_copy) pop %r15 /* Offset to __x86_return_thunk would be wrong here */ + ANNOTATE_UNRET_SAFE ret int3 .L__enc_copy_end: diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index 565062932ef1..38b73e7e54ba 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -70,6 +70,7 @@ SYM_CODE_START(hypercall_page) .rept (PAGE_SIZE / 32) UNWIND_HINT_FUNC .skip 31, 0x90 + ANNOTATE_UNRET_SAFE RET .endr diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 1eebfa422153..eac6b89660b1 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1799,8 +1799,9 @@ static int read_retpoline_hints(struct objtool_file *file) } if (insn->type != INSN_JUMP_DYNAMIC && - insn->type != INSN_CALL_DYNAMIC) { - WARN_FUNC("retpoline_safe hint not an indirect jump/call", + insn->type != INSN_CALL_DYNAMIC && + insn->type != INSN_RETURN) { + WARN_FUNC("retpoline_safe hint not an indirect jump/call/ret", insn->sec, insn->offset); return -1; } @@ -3051,7 +3052,8 @@ static int validate_retpoline(struct objtool_file *file) for_each_insn(file, insn) { if (insn->type != INSN_JUMP_DYNAMIC && - insn->type != INSN_CALL_DYNAMIC) + insn->type != INSN_CALL_DYNAMIC && + insn->type != INSN_RETURN) continue; if (insn->retpoline_safe) @@ -3066,9 +3068,14 @@ static int validate_retpoline(struct objtool_file *file) if (!strcmp(insn->sec->name, ".init.text") && !module) continue; - WARN_FUNC("indirect %s found in RETPOLINE build", - insn->sec, insn->offset, - insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); + if (insn->type == INSN_RETURN) { + WARN_FUNC("'naked' return found in RETPOLINE build", + insn->sec, insn->offset); + } else { + WARN_FUNC("indirect %s found in RETPOLINE build", + insn->sec, insn->offset, + insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); + } warnings++; } |